In general, single-use bioreactors are a cheaper alternative to traditional glass/steel bioreactors. Moreover, single-use bioreactors come in wide range of size and form factors, allowing for easier storage and configurability as compared to steel/glass reactors. There is an increasing demand for single-use technologies in the bioprocess industry. However, there are limited and expensive choices for single-use sensors to fit into the bioreactors. Thus, a need exists for single-use sensors for reactors in general, including bioreactors. The invention is directed to these, as well as other, important ends.